Brazil will begin tracking patients with type 5 diabetes, a little-known form of the disease linked to malnutrition. The initiative, a first in Brazilian health care and rare worldwide, was confirmed on Wednesday (26) by the SBD (Brazilian Diabetes Society) during a congress in Rio de Janeiro, according to Folha de S.Paulo. The first targets will be the North and Northeast regions, which concentrate the largest share of Brazilians living with food insecurity and malnutrition.
What type 5 diabetes is
The condition was described more than 70 years ago and has had other names, such as tropical diabetes and type J diabetes, because the first case was recorded in Jamaica in 1955. In 2025, the International Diabetes Federation (IDF) recognized the new classification, in practice a renaming of what was called malnutrition-related diabetes. The disease mainly affects teenagers and very thin young adults, with a body mass index below 18.5 to 19, and is more common in low- and middle-income countries such as India, Thailand, Uganda, Ethiopia and Nigeria, according to the SBD.
The main risk today is confusion with type 1 diabetes, which also appears early in life and in underweight people. The mechanism, however, is different. In type 1, an autoimmune reaction halts insulin production by the pancreas, and the patient can develop ketoacidosis, an emergency that makes the blood acidic and can be fatal. In type 5, severe calorie and protein malnutrition in the womb or in early childhood reduces the insulin-producing cells, but the body keeps a small reserve of the hormone. For that reason, the SBD explains, these patients do not develop ketoacidosis and usually need smaller insulin doses. "It was unanimously agreed to call this diabetes type 5 because it is different from all others cataloged so far: it occurs in very thin people, usually under 30, who will need a smaller insulin replacement," physician Hermelinda Pedrosa, vice-president of the IDF and an SBD member, told Folha.
What is confirmed and what remains a hypothesis
The tracking announcement is the concrete fact so far. The rest remains open. Brazil has no prevalence data on type 5. "There may be cases, but they are possibly labeled as type 1 because of the overlap of characteristics, such as the early age of onset and the low BMI," says physician Fernando Valente, an SBD director, in a text published by the organization. The suspicion heard by Folha is that a relevant number of Brazilians treated as type 1 actually have type 5, which exposes patients to inadequate treatment. International studies indicate the condition is more frequent in men in rural areas, who often never receive the correct diagnosis and accumulate complications such as blindness, kidney and heart problems and lower-limb amputations.
The SBD already keeps on its website a type 5 screening form aimed at health professionals, based on the algorithm proposed by the IDF, with clinical criteria to identify suspected cases. The federation has also created a working group to develop, within two years, formal diagnostic criteria and therapeutic guidelines for the disease.
For patients, the practical guidance is straightforward. Anyone under 30 who is very thin and lives with a diabetes diagnosis, especially if there was malnutrition in childhood, can raise the topic at the next appointment. The correct diagnosis changes management: besides smaller insulin doses, type 5 treatment includes proper replacement of calories, protein and micronutrients. No medication change should be made on one's own; any adjustment belongs with the doctor following the case.